Optical trapping of ultracold dysprosium atoms: transition probabilities, dynamic dipole polarizabilities and van der Waals C6 coefficients. (15th December 2016)

• Record Type: Journal Article
• Authors: Li, H; Wyart, J-F; Dulieu, O; Nascimbène, S; Lepers, M
• Is Part Of: Journal of physics. Volume 50:Number 1(2017:Jan. 01)
• Publication Date: 2016-12-15
• Subjects: ultracold atoms and molecules -- dipolar gases -- atomic-structure calculations -- laser-cooling and trapping -- atomic spectroscopy -- polarizabilities -- van der Waals C6 coefficients; Atoms -- Periodicals; Molecules -- Periodicals; Optics -- Periodicals; Nuclear physics -- Periodicals; 539.6
• DOI: 10.1088/1361-6455/50/1/014005
• Languages: English
• ISSNs: 0953-4075

Abstract

Abstract: The efficiency of the optical trapping of ultracold atoms depends on the atomic dynamic dipole polarizability governing the atom-field interaction. In this article, we have calculated the real and imaginary parts of the dynamic dipole polarizability of dysprosium in the ground and first excited levels. Due to the high electronic angular momentum of those two states, the polarizabilities possess scalar, vector and tensor contributions that we have computed, on a wide range of trapping wavelengths, using the sum-over-state formula. Using the same formalism, we have also calculated the C 6 coefficients characterizing the van der Waals interaction between two dysprosium atoms in the two lowest levels. We have computed the energies of excited states and the transition probabilities appearing in the sums, using a combination of ab initio and least-square-fitting techniques provided by the Cowan codes and extended in our group. Regarding the real part of the polarizability, for field frequencies far from atomic resonances, the vector and tensor contributions are two-orders-of-magnitude smaller than the scalar contribution, whereas for the imaginary part, the vector and tensor contributions represent a noticeable fraction of the scalar contribution. Finally, our anisotropic C 6 coefficients are much smaller than those published in the literature.